In the book, Edmund and Lucy Pevensie are drawn back to Narnia, this time with their despised cousin Eustace in tow. They find themselves on the Dawn Treader, the ship of King Caspian, who has embarked on a quest to find the lost Lords of Narnia.
During a storm, the ship is damaged and they put in at a nearby island to make repairs. Eustace, who has been a whiny nuisance since his arrival, wanders off to avoid doing any work. He stumbles upon a dragon's lair when he ducks into a cave to get out of the rain. The dragon's treasure infects Eustace with greed and he fills his pockets with riches and puts a large gold bracelet on his arm before falling asleep. When Eustace wakes up, he finds to his horror that he has turned into a dragon, the bracelet now like a painful vice on his arm. It gradually dawns on him that his bad behaviour has resulted in this terrible fate.